Frisk tries to convince Sans to kill him so that they could accomplish a better timeline. He refuses, and Frisk uses his time to defeat Sans, giving him his iconic nickname 'Cross' before XGaster resets back to the day the brothers took Undyne's test. As it turns out, everyone was now against XGaster thanks to Frisk restoring their memories, and because of his ignorance to see the trouble caused by his 'father', everyone turned against him, including his own brother.